EMDR FORUM ARCHIVE, 2000
Re:Maxfield & Hyer meta-analysis: A few questions
Cahill · 11/02/02 at 11:32 PM ET
Louise: Regarding your point #1 on internal validity, you take a strong methodological position here and I really respect that. In fact, I endorse that. At present, the strongest evidence for the efficacy of EMDR comes from studies that ustilized the full standard protocol (e.g., Rothbaum, S. Wilson et al.). The dismantling studies that have failed to find evidence for eye movements generally also fail to provide evidence that EMDR works. This is for one of two reasons. Some studies failed to find evidence for EMDR because they did not include a waitlist control group. Renfrey and Spates, for example, included EMDR and then two alternatives that were identical to EMDR except in the area of eye movements. One control group used blinking lights that alternated left-right to induce eye movements (to determine if there was something about a therapist directing the eye movements) and then a stationary blinking light to assess the role of left to right eye movements per se. All groups got better, and there were no differences between groups. Because all groups got equally better, the improvement could have been due to anything, including the effects of repeated assessments and common factors (such as expectancy effects) that have nothing to do with EMDR per se. Thus, Renfrey and Spates does not provide any convincing evidence for the efficacy EMDR. The other reason some dismantling studies do not provide support for EMDR is that, although they included appropriate control groups, EMDR did not beat the control group. This was the case with the Boudewyns et al. (1993) study in which EMDR was not superior to millieu therapy. Because we can't prove the null hypothesis, it always remains possible that the lack of a treatment effect was related to how EMDR was implemented (e.g., too few sessions). Because of the pattern of results across dismantling studies, the best evidence for EMDR involves studies that included eye movements. So, as a PRACTICAL matter, it may be defensible to continue to use eye movements. However, it seems to me that it should be an important item in the research agenda of EMDR to clearify this confusing mess. Moreover, the practical decision to use eye movements as the standard treatment in no way changes the fact proponents of EMDR have yet to meet the burden of evidence for the use of eye movements. Now, here is something I find intersting. I have previously pointed out that Shapiro changed EMD after the 1989 study and yet insists, in the complete absence of data, that EMDR is superior to EMD. Similarly, Sandra repeatedly states that a special protocl must be used with people who are dissociative. Both the change from EMD to EMDR and the changes of EMDR to the dissociative EMDR protocol involve violating the the validity of EMD. In fact, this was a major point of mine regarding the off-hand rejection of the Lytle data because they didn't use the updated protocol. When I pointed out that such changes were made in the absence of data, and therefore in priciple could actually have reduced the effectiveness of EMDR (relative to EMD or relative to EMDR Dissociation Protocol), I'm told that such changes justified based on commen sense and clinical observation (See Sandra's post from 10/28/02, 5:05 pm in response to my Comment on Point 1). Now, I realize I'm carrying on conversations with different people, and that Sandra may not endorse the strong methodological position that Louise advanced. However, we can't have it both ways folks. We can't justify changes made by Shapiro, or Paulson-Inobe in the absence of data on the grounds of "common sense" and "clinical experience", but reject changes made by Devilly.
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